mailbox: mailbox-test: add support for separate tx/rx buffer with single channel

This patch adds support for different MMIO region for Tx and Rx paths.
If only one region is specified, it's assumed to be shared between Rx
and Tx, thereby retaining backward compatibility.

Also in order to support single channel dealing with both Tx and Rx with
dedicated MMIO regions, Tx channel itself is assigned to Rx if MMIO
regions are different and Rx is not specified.

Acked-by: Lee Jones <[e-mail]>
Signed-off-by: Sudeep Holla <[e-mail]>
Signed-off-by: Jassi Brar <[e-mail]>

drivers/mailbox/mailbox-test.c

···
 
 struct mbox_test_device {
 	struct device		*dev;
-	void __iomem		*mmio;
+	void __iomem		*tx_mmio;
+	void __iomem		*rx_mmio;
 	struct mbox_chan	*tx_channel;
 	struct mbox_chan	*rx_channel;
 	char			*rx_buffer;
···
 	 * A separate signal is only of use if there is
 	 * MMIO to subsequently pass the message through
 	 */
-	if (tdev->mmio && tdev->signal) {
+	if (tdev->tx_mmio && tdev->signal) {
 		print_hex_dump_bytes("Client: Sending: Signal: ", DUMP_PREFIX_ADDRESS,
 				     tdev->signal, MBOX_MAX_SIG_LEN);
 
···
 	unsigned long flags;
 
 	spin_lock_irqsave(&tdev->lock, flags);
-	if (tdev->mmio) {
-		memcpy_fromio(tdev->rx_buffer, tdev->mmio, MBOX_MAX_MSG_LEN);
+	if (tdev->rx_mmio) {
+		memcpy_fromio(tdev->rx_buffer, tdev->rx_mmio, MBOX_MAX_MSG_LEN);
 		print_hex_dump_bytes("Client: Received [MMIO]: ", DUMP_PREFIX_ADDRESS,
 				     tdev->rx_buffer, MBOX_MAX_MSG_LEN);
 	} else if (message) {
···
 {
 	struct mbox_test_device *tdev = dev_get_drvdata(client->dev);
 
-	if (tdev->mmio) {
+	if (tdev->tx_mmio) {
 		if (tdev->signal)
-			memcpy_toio(tdev->mmio, tdev->message, MBOX_MAX_MSG_LEN);
+			memcpy_toio(tdev->tx_mmio, tdev->message, MBOX_MAX_MSG_LEN);
 		else
-			memcpy_toio(tdev->mmio, message, MBOX_MAX_MSG_LEN);
+			memcpy_toio(tdev->tx_mmio, message, MBOX_MAX_MSG_LEN);
 	}
 }
 
···
 
 	/* It's okay for MMIO to be NULL */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	tdev->mmio = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(tdev->mmio))
-		tdev->mmio = NULL;
+	tdev->tx_mmio = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(tdev->tx_mmio))
+		tdev->tx_mmio = NULL;
+
+	/* If specified, second reg entry is Rx MMIO */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	tdev->rx_mmio = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(tdev->rx_mmio))
+		tdev->rx_mmio = tdev->tx_mmio;
 
 	tdev->tx_channel = mbox_test_request_channel(pdev, "tx");
 	tdev->rx_channel = mbox_test_request_channel(pdev, "rx");
 
 	if (!tdev->tx_channel && !tdev->rx_channel)
 		return -EPROBE_DEFER;
+
+	/* If Rx is not specified but has Rx MMIO, then Rx = Tx */
+	if (!tdev->rx_channel && (tdev->rx_mmio != tdev->tx_mmio))
+		tdev->rx_channel = tdev->tx_channel;
 
 	tdev->dev = &pdev->dev;
 	platform_set_drvdata(pdev, tdev);